The headphones can also be seen here http://29.media.tumblr.com/tumblr_lgyz1o5KL51qzftruo1_500.jpg
and also at his wikipedia instrument page:
https://en.wikipedia.org/wiki/John_Lennon%27s_musical_instruments

I bought these 10 years ago when I was going to school for music business and was taking an engineering/production coarse. They are still some of the highest rated and most popular headphones in their price range. I highly recommend getting a pair. The only drawback is the cable will most definitely need replacing and you MUST order the replacement from AKG.

These are my favorite cans for my own listening pleasure and ALWAYS will be. They are the classic semi-open backed option. The drivers sound great and thanks to the open backs they have fantastic, speaker-like fidelity and are less fatiguing than cans typically are. Their drawbacks are strictly a lack of isolation from loud sources like guitar amps when you are tracking next to them and a little bit of spill out their open backs into sensitive microphones when you laying down takes on an acoustic instrument. Often the spill is so negligible you can use them over a closed-back headphone anyway...